You do not need to compile to have it incorporated into the "official" pakset, you simply need to send your graphics to James or make them publicly available and send us a link. It would of course be best if you set up your own Github repository from which James could simply merge the changes you make into the main repository. Would you be interested in a guide into setting up a Github repository for that purpose?

What I meant by compiling was compiling the pakset itself (step 5 of the tutorial with makeobj etc.), not rendering the graphics (step 3 of the tutorial, which isn't even called compiling anyway). To contribute new liveries to the pakset you should ideally complete steps 2 to 4 of the tutorial. You can also do step 5 if you want to test the graphics in-game yourself, which would save us some work if there are errors but isn't strictly necessary.

Git/Github is free. What you need to do is clone the Pak128.Britain-Ex repository (search for instructions on how to do this) to your own repository on Github, and add your modified files to your cloned repository. You then push your changes (the addition of your files and changes to any existing files - if you are adding new vehicles rather than just adding liveries, do not forget to add translation texts for each new vehicle to en.tab also) to your repository on Github. I can then merge your changes into my branch on Github so that these are automatically compiled.

While you do not need to provide compiled versions, you do need to compile them yourself to test that they work, as you need to be the person testing/debugging your new additions.

That is some great progress! Now you will need to clone the main pakset repository and commit the rendered graphics and modified .dat files to it. When doing so, make sure you clone James's repository and not mine, as that is the one from which the official pakset is made. Also, make sure your commit messages describe what changes and additions you make in each commit.